A Dose Counting System

Abstract

A dose counting system of an injection device or of a module configured to be used with or applied to an injection device, the dose counting system comprising: a sensor arrangement comprising a first sensor configured to output a first signal and a second sensor configured to output a second signal, wherein the first sensor and the second sensor have an angular offset relative to each other and wherein the sensor arrangement is configured to detect movement of a rotary encoder system relative to the sensor arrangement during dosing of a medicament; and a processor configured to: compute numerical derivatives of the first signal and the second signal; detect a peak in the derivative values of the first signal and a peak in the derivative values of the second signal when the first and second derivative signal values exceed a predefined threshold; determine that a unit of medicament has been administered when the peaks in the derivative values of the first signal and the derivative values of the second signal are simultaneous, the peak in the derivative values of the first signal has a different sign from the peak in the derivative values of the second signal and the peak in the derivative values of the first signal has a different sign for the previous peak in the derivative values of the first signal; and determine a medicament dosage administered by the injection device by counting the administered units of medicament.

1 .- 15 . (canceled) 
     
     
         16 . A dose counting system of an injection device or of a module configured to be used with or applied to an injection device, the dose counting system comprising:
 a sensor arrangement comprising a first sensor configured to output a first signal and a second sensor configured to output a second signal, wherein the first sensor and the second sensor have an angular offset relative to each other and wherein the sensor arrangement is configured to detect movement of a rotary encoder system relative to the sensor arrangement during dosing of a medicament; and   a processor configured to:
 compute numerical derivatives of the first signal and the second signal; 
 detect a peak in the derivative values of the first signal and a peak in the derivative values of the second signal when the derivative values of the first signal and the derivative values of the second signal exceed a predefined threshold; 
 determine that a unit of medicament has been administered when the peak in the derivative values of the first signal and the peak in the derivative values of the second signal are simultaneous, wherein the peak in the derivative values of the first signal has a different sign from the peak in the derivative values of the second signal and the peak in the derivative values of the first signal has a different sign from a previous peak in the derivative values of the first signal; and 
 determine a medicament dosage administered by the injection device by counting the administered units of medicament. 
   
     
     
         17 . The dose counting system according  claim 16 , wherein the processor is further configured to calculate a moving average of a series of values of the first signal and the second signal. 
     
     
         18 . The dose counting system according  claim 17 , wherein the moving average comprises a mean of a first set of values minus a mean of a second set of values of the same sensor, wherein the first set of values and the second set of value include the same number of values. 
     
     
         19 . The dose counting system according  claim 18 , wherein the first set of values and the second set of values are overlapping. 
     
     
         20 . The dose counting system according  claim 17 , wherein the processor is further configured to calculate a moving median of a series of values of the first signal and the second signal. 
     
     
         21 . A dose counting system according  claim 20 , wherein the moving median comprises a median value of a first set of values minus a median value of a second set of values, wherein the first set of values and the second set of values contain the same number of values. 
     
     
         22 . The dose counting system according to  claim 16 , wherein the injection device comprises an injection button configured to be pressed in order to administer a dose of medicament from the injection device. 
     
     
         23 . The dose counting system according to  claim 22 , wherein the processor is further configured to determine that the injection button has been pressed or released when the peaks in the first signal and the second signal have a same sign. 
     
     
         24 . The dose counting system according to  claim 23 , wherein the processor is further configured to, in response to determining that the injection button has been pressed, initiate a communication pairing with an external device or execute a data synchronisation with the external device. 
     
     
         25 . The dose counting system) according to  claim 24 , wherein the communication pairing is a Bluetooth pairing. 
     
     
         26 . The dose counting system according to  claim 23 , wherein the processor is further configured to, in response to determining that the injection button has been released, initiate a manual data synchronisation. 
     
     
         27 . The dose counting system according to  claim 22 , wherein the processor is further configured to, in response to determining that the injection button has been released, cause an end of dose indication to be outputted. 
     
     
         28 . The dose counting system according to  claim 16 , wherein the rotary encoder system comprises an encoder ring comprising a plurality of substantially light reflective flags arranged circumferentially around the encoder ring in accordance with a predefined angular periodicity. 
     
     
         29 . A computer-implemented method of operating a dose counting system of an injection device or of a module configured to be used with or applied to an injection device, the dose counting system comprising:
 a sensor arrangement comprising a first sensor configured to output a first signal and a second sensor configured to output a second signal, wherein the first sensor and the second sensor have an angular offset relative to each other and wherein the sensor arrangement is configured to detect movement of a rotary encoder system relative to the sensor arrangement during dosing of a medicament; and   a processor;   
       wherein the method comprises:
 computing numerical derivatives of the first signal and the second signal; 
 detecting a peak in the derivative values of the first signal and a peak in the derivative values of the second signal when the first and second derivative values exceed a predefined threshold; 
 determining that a unit of medicament has been administered when the peaks in the derivative values of the first signal and the derivative values of the second signal are simultaneous, the peak in the derivative values of the first signal has a different sign from the peak in the derivative values of the second signal and the peak in the derivative values of the first signal has a different sign for the previous peak in the derivative values of the first signal; and 
 determining a medicament dosage administered by the injection device by counting the administered units of medicament. 
 
     
     
         30 . The computer-implemented method of  claim 29 , further comprising calculating a moving average of a series of values of the first signal and the second signal. 
     
     
         31 . The computer-implemented method of  claim 30 , further comprising calculating a moving median of a series of values of the first signal and the second signal. 
     
     
         32 . The computer-implemented method of  claim 30 , further comprising calculating a moving median of a series of values of the first signal and the second signal. 
     
     
         33 . The computer-implemented method of  claim 29 , wherein the injection device comprises an injection button configured to be pressed in order to administer a dose of medicament from the injection device, and
 wherein the method further comprises determining that the injection button has been pressed or released when the peaks in the first signal and the second signal have a same sign.   
     
     
         34 . The computer-implemented method of  claim 33 , further comprising:
 in response to determining that the injection button has been pressed, initiating a communication pairing with an external device or execute a data synchronisation with the external device.   
     
     
         35 . The computer-implemented method of  claim 33 , further comprising: in response to determining that the injection button has been released, initiating a manual data synchronisation.